Apple

iPhone

iPad

iOS

Jailbreak

Cydia

From the maker of GPsPhone comes psx4iPhone, a Playstation emulator for iPhone. Its not quite a release yet, but zodttd, the developer, says a release could be only a few days away.

From zodttd:

What can you look forward to in the first release of psx4iphone? Depends on how the beta testing goes. I will be working on the existing dynarec (cpu emulation) quite a lot to improve performance as it will be required. The screen scaling and screen placement will be drastically improved over the above images. Memory card support will work, and save states might work. Sound will be implemented as well. The interface/gui will be very similar to gpSPhone's just with 4 hard buttons instead of just A+B, and L2 and R2 buttons. A rough estimate would be about 75% of games will be compatible. With such a large library of games, this may or may not include your favorite game. Performance will have to be increased about 25% to get a good portion of games running smoothly. This can be done.